Fuel injection device for internal



Y H. JUNKERS May 29, 1934.

FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINES Original FiledJan.- 14, 1932 I'm 62160)".- lva'ya Jan/fem Reissued May 29, 1934 UNITEDSTATES PATENT OFFICE ial u FUEL INJECTION DEVICE FOR. INTERNALCOMBUSTION ENGINES Hugo Junkers, Dessau, Germany Original No.l,901.814,,dated Serial No. 588,592, January March 14, 1933, 14, 1932.Application for reissue November 25, 1933, Serial No. 699,762. InGermany January 17, 1981 11 Claims. (Cl. 299-1075) My invention relatesa) fuel injection devices for internal combustion engines, and moreparticularly to solid-injection fuel admitting devices of the type inwhich a needle is permanently ap- 6 plied under pressure to a seat inthe casing ofthe injection device. It is an object of my invention toimprove a fuel injection device of the type described with a view topreventing excessive pressure and deformation at the seat of the needlein the casing. i

To thisend, in combination with means such as a cap nut anchored on oneof the members,'for instance the casing, and exerting thrust on theother member, for instance the needle, I provide 15 means for limitingthe relative movement of the free ,ends of the two members under theaction of the thrust;

In injection devices of the type described as heretofore designed inwhich the needle is perend of the casing so as to make a tight fltthereon, the seating face is subjected to.deformation if the needle isapplied to the seat at excessive pressure. Deformation of the face isdetrimental because it interferes with the tight it of the needle on itsseat, and because defective fit cause irregularity of the issuing jetoffuel.

According to the present invention the pressure which the needle exertson the seat in the casing. is limited in such manner that it will notoverstep .a certain predetermined limit even if the thrust exerted onthe needle by the cap nut or the like should exceed this limit. v Inreducing my invention to practice I may for instance provides lug,preferably a collar, at or near the' freeend of the needle or on amember forming an extension of the needle, and

. an abutment for the lug or collar on the casing.

'I'he mating faces on the lug or collar and of the abutment are soarranged that in the unstressed condition of the needle they are spaceda definite distance. The clearance between the facesmust be exactlyequal to the relative displacementofthefreeendsoftheneedieand '45aforesaid, for instance the cap nut, exerts on the casingandthecompression or upsetting it exertson the needle when the needlehas been applied-to its seatin the casing under the predeterminedpressure. By the t deforms .tion-of theneedle and the casing the needleis appliedsto its seat, while at the same time the mating faces of theabutment on the casing and theluaorcoliaronthen'eedlemovetowardeach .55other and iinally engage. At this moment the manently applied to aseating face at the inner the casing under the tension which the meanspressure under which the needle applied to its seat, has attained thepredetermined limit which is a function of the size and the elasticitycoeflicients of the needle and the casing. If the cap nut or other meansis operated further, it will onlyincrease the pressure at which the lugor collar on the needle and the abutment on the casing engage, but notthe pressure which the needle exerts on its seating face. In otherwords,

the predetermined, seating pressure of the needle will never overstepits limit even if the cap nut or other means is operated after the limithas been attained. This operation only results in an increase of .thepressure at which the mating faces engage, but never in overstressingand 0 deformation of the seating faces of the needle and the casing. sothat the tight fit of the faces is not interfered with.

It is another object of my invention to so design an injection device ofthe type referred to 76 that-the clearance between the lug or collar onthe needle and theabutment on the casing in unstressed condition willnot become unconveniently small. In injection devices of short overalllength with correspondingly small deforma- '80 tions it is diiiicult tomachine the lug orcollar' on the needle and the abutment on the casingto exactly the distance required.

For the purpose of eliminating this diiiiculty I artificially increasethe resiliency of the casing or the 'needle or both, which may beefl'ected by reducing the section of one or both members; or renderingthem more resilient in some other way. For instance the casing or theneedle may be equipped with any number of grooves in its outer 9Q and/orinner wall in a plane extending transversely to the needle axis.

In the drawing aflixed to this specification and forming part thereofvarious types of injection devices embodying my invention areillustrated di-"illi agrammatically by way of example.

In the drawing 1 Fig. 1 is an axial section of an injection device ofnormal length in which the lug or collar on the needle is integral withthe needle.

0 Fig. 2 is an axial section of a shorter injection .device in which thesection of the needle is reduced for a portion of itslength in order toincrease its resiliency, as and for the purpose specifled, and the lugor collar is formed on a detach -able extension of the needle.

Fig. 3 is an axial section of an injection device having the same lengthas the injection device illustrated in Fig. 2, but-in which the sectionof the casing is reduced for a portion of its length 1andthelugorcollarisformedintegralwiththe needle. as shown in Fig. 1, and

Fig. 4 is an axial section of a casing'having transverse grooves in itsinner and outer perimeters for increasing its resiliency.

Referring now to the drawing, in all figures 30 is a portion of thecylinder head, 1 is the casing which is inserted in the cylinder head bya thread 29 near its lower end, 2 is the needle which is axially boredat 9, l and 11 are diverging fuel-passages.extending from the inner endof the bore 9, 3 is a tapered seating face at the inner end ofthe'needle 2, and 4 is a corresponding face at the innerend of thecasing 1. 12,13 are fuel discharge grooves extending from the passagesand 11 to the ejection opening 18 at the centre of the casing. 23 is athread at the outer end of the casing 2, 5 is sup nut on the thread and6 is a lug on the needle,here shown as a collar, which is engaged by theinwardly projecting flange of the cap nut so that by turning the cap nutthrust is exerted on the needle. 20 is the face at the needle forlimiting the relative displacement of the needle and the casing, as andfor the purpose specified, and

21 is the abutment at the outer-end of the casing.

'lisafuelmplypipewlthitsboreilinlinewithtbebore9oftheneedle,19isaplugsurrounding theendofthepipe7,andl4isacapnut onthe threaded upper end 1'! of the needle, with its eron the. plug 19 for twoormoreofwhichmaybeprovlded. Thesepassagesopenintothetaperedseatin'gfacesof whichisappliedtotheseatingface lby-thecap nut 6.andthefuel iseonductedtotheejectionopenmglathrou htheiinegrooves12.13whichareformedinthe seatingfscesottheneedle I-iiisturnedonitsthreadflth'ecasingiisundertensionandtheneedleflisundercompremonandtbetwomembersareresilientlydeformedthecasingbeingstretchedandtheneedleupset,untilthe faces20and21engage.Atthismomentthe force whichappliestheseat3oftheneedleltotheseat4inthecasing 2.hasthepredeter'mihed imoimtwhichmustnotbeexceeded.Ifbyinadverteneethenutbismrnedfurtberitwillonlyincreasethe-pressureatwhichthefacesmandmengagebutnot-thepressureontheseatingfaces.

cousequentlythe ressm-eatthe seating faces 8."

4csnnotbeincreasedbeyond'thepredeterminedsectionoi'theneedle2isreducedat3Lsothatit.

becomes more resilient and'the amount to whichastoapplytheirseatingfacesontoeachother,

In the example illustrated in Fig. 2 the lug or 'collar 6 at the needleand the plug 19 at the end of the supply pipe '7 are combined into aseparate detachable member 22 which is placed on the needle as an axialextension, and held against turning by a pin 24. This has the advantagethat the flange member may be'exchanged if required, without involvingthe needle.

Referring now to Fig. 3,the flange 6 is integral with the needle 2 asillustrated in Fig. 1 but in order to obtain the resiliency required forthe exact sizing of the clearance between 20 and 21, the section of thecasing 2 is reduced at 32.

Fig. 4 illustrates another solution of the problem of increasing theresiliency of comparativelyshort members. Here the casing 1 has threegrooves 25 in its inner, and two grooves 26 in its outer wall, the planeof the grooves extending at right angles to the axis of the casing. Fullsections 2'1 extend between each outer and inner groove, and the casingresembles a cylindrical diaphragm such as used in aneroid barometers.

Obviously the several details illustrated are not limited to theparticular type of injection device in which they have been shown.

Thus. the detachable member 22 might also be adapted to the injectiondevices illustrated in Figs. 1 and 3 instead of the fixed collar 6, thesection of the casing in the injection device illustrated in Fig. 2. orthe section of the needle in the injection device-illustrated in Fig. 3might be reduced so that the resiliency of both the needle and thecasing are artificially increased. The diaphragm-like design of thecasing l illustrated inFig.4mightalsobeadaptedtotheneedle 2.-Iwishittobeunderswodthatldonot desiretobelimitedtnthe exact detailsofconstruction shown and described for obviousmodificationswilloccurtoapersonskilledintheart.

I claim:-

1. a solid-injection fuel admitting device fol internal combustionengines comprising a casing. 1

aneedlewithafuelpassageinsertedinsaidcasing, co-acting seating faces onsaid needle and saidcasing,meansanchored on one of saidmembers'forexertingthrustonthe other memberso and means for limiting therelative movement of the free ends of said members under'the action ofthe thrust.

2. A staid-injection fuel admitting device for internal combustionengines comprising a casing, 13-)aneedlewithafuelpassageinsertedinsaidcasing,coactingseatingfacesonsaidneedleandsaidcasing,alugononeofsaidmember,andan abutment on the other member adaptedto be engaged by said 1118, said lug and said abutment being so arrangedthat the clearance between them in unstressed condition of the twomembers is equal to the distance through which the free ends of saidmembers are displaced with respect to each other when said seating facesare .applied to each other at a predetermined pressure.

3. A solid-injection fuel admitting device for internal combustionengines comprising a casing, a needle with a fuel passage inserted insaid casing, coacting seating faces on said needle and said casing,means anchored on one of said members for exerting thrust on the othermember so as to apply their seating faces onto each other, means forlimiting the relative movement of the free ends of said members underthe action of thethrushandmeansfortheresllmey ofonsofsaidmembeis.

LAsolid-iniectionfueladmittingdevioefor internalenginescomprisingacasinghavingapartlyreducedsectiomaneedlewitha fuel inserted in said casing.coacting seating faces on said needle andsaid easing,

casing, having a partLv reduced section, coacting seating faces on saidneedle and said casing, means anchored on one of said members forexerting thrust on the other member so as to apply their seating facesonto each other, and means for limiting the relative movement of thefree ends of said members under the action of the thrust.

6. A solid-injection fuel admitting device for internal combustionengines comprising a casing, a needle with a fuel passage inserted insaid casing, coacting seating faces on said needle and said casing,means anchored on one of said members for exerting thrust on the othermember so as to apply their seating faces onto each other, and means forlimiting the relative movement of the free ends of said members underthe actionofthethmshoneofsaidmembersbeing designed like a cylindricaldiaphragm.

"l. A solid-injection fuel admitting device for internal combustionengines comprising a easing, aneedlewith afuel e insertedin saideasing,coactingseatingfacesonsaldneedleandsaidcasing,meansanehoredononeofsaidmemhers-for exerting thrust on theother member soastoapplytheirseatingfacesontoeaehother, and means forlimiting the relative t of tbefreeendsofsaidmembersundertbeaetionofthetbrustmneofsaidmembershavinggrooves extending to its axis.

.8.Asolid-iniectionfueladmittingdevicefor internal combustion enginescomprisinga cadng,

aneedlewithafuel insertedinsaidcasing, coacting seating f on said needleandsaidcasing,meansanchoredonsaidcasingforexertingthrustonsaidneedleandsaidcasingso as to apply said seating facesto each other, and means for limiting the relative movement of the freeends of said casing and said needle under the action of the thrust.

9. A solid-injection fuel admitting device for internal combustionengines comprising a casing, a needle with a fuel passage inserted insaid casing, coacting seating faces on said needle and said casing,means anchored on said casing for casing, coacting seating faces on saidneedle and said casing, means anchored on said casing for exertingthrust on said needle and "said casing so as to apply said seating facesto each other, a

detachable member forming an axial extension of said needle, a lug onsaid extension, and an abut- 1 ment on said casing adapted to be engagedby said lug, the clearance between said lug and said abutment being sodetermined that thepressure at said seating faces is limited to apredetermined amoimt.

11. A solid-injection fuel admitting device for internal combustionengines comprising a casing, a needle inserted in said casing, means forsupplyingfueltothecasingextendingintheaxial direction of said casing,coacting seating faces onsaidneedleandsaidcasing,aeollaronsaidneedlefacingtheendfaceofsaidcasingand means anchored on one'of saidmembers for exerting thrust on the other member so as to apply theircoacting seating faces onto each other and said collar onto the end faceof said casing.

HUGO JUNKIRB.

